As a rule, combustion machines for motor vehicles have a cooling system in which a coolant is pumped through at least one cooling circuit by means of one or more pumps and, in the process, it picks up thermal energy from components that are integrated into the cooling circuit, especially from an internal combustion engine as well as from an oil cooler and/or an intercooler. In an ambient heat exchanger, the so-called main water cooler, as well as at times, in a heating heat exchanger, this thermal energy is subsequently released into the ambient air; in the case of the heating heat exchanger, this energy is released into the ambient air provided for the climate control of the interior of the motor vehicle.
Cooling systems of modern motor vehicles often have several cooling circuits. For instance, it is a known approach to provide a so-called large or main cooling circuit as well as a small cooling circuit, sections of which have an integrated configuration, whereby a thermostat-controlled valve is used to convey the coolant either via the main cooling circuit or via the small cooling circuit. This is done as a function of the temperature of the coolant, so that, for example, during the warm-up phase of the combustion machine, when the coolant has not yet reached a prescribed operating temperature, the coolant is conveyed in the small cooling circuit, thereby bypassing the main cooling circuit, that is to say, the ambient heat exchanger in which the coolant is cooled mainly by heat transfer to the ambient air. In contrast, once the coolant has reached the operating temperature range, the coolant is conveyed in the large cooling circuit by means of the thermostat-controlled valve, so that overheating of the cooling system is prevented, thanks to the transfer of heat from the coolant to the ambient air. The heating heat exchanger, as the second ambient heat exchanger, in contrast, is normally integrated into the small cooling circuit, as a result of which the interior of the motor vehicle can already be heated during the warm-up phase of the combustion machine.
The (main) coolant pump of the cooling system is normally driven mechanically by the internal combustion engine of the combustion machine. Its pumping capacity is thus fundamentally proportional to the rotational speed of the crankshaft of the internal combustion engine. Even though the demand for cooling capacity also tends to increase as the rotational speed of the internal combustion engine rises, in many operating states, the cooling capacity that can theoretically be achieved by the operation of the pump does not correspond to the actual demand for cooling capacity. Since a sufficiently high cooling capacity should be available in all operating states, such mechanically driven pumps are often over-dimensioned. Consequently, the efforts aimed at reducing the fuel consumption of motor vehicles have led to the development of mechanically driven coolant pumps that can be regulated within certain limits in terms of their volume flow. Such a regulatable mechanically driven coolant pump is disclosed, for example, in German patent application DE 10 2010 044 167 A1.
When it comes to the cooling systems of modern motor vehicles, the main regulation of the volume flow of coolant can thus be achieved by means of regulatable coolant pumps, whereas the distribution of the volume flow to the individual components that each have a different demand for cooling can be achieved by valves that are actively controlled, especially by means of thermostats. German patent application DE 103 42 935 A1, for instance, discloses a combustion machine with a cooling circuit encompassing a pump that is mechanically driven by an internal combustion engine. The pump capacity is thus dependent on the rotational speed of the internal combustion engine. In order to attain individually adapted volume flows of the coolant for several heat exchangers integrated into the cooling circuit, especially such as cooling ducts of a cylinder block and of a cylinder head of the internal combustion engine, as well as for a heating heat exchanger that serves for the interior heating of a motor vehicle driven by a combustion machine, a plurality of control valves that can be actuated individually are integrated into the cooling circuit. German patent application DE 103 42 935 A1 also discloses that the ducts of the cylinder block and of the cylinder head are connected in parallel, which makes it possible to individually regulate the cooling capacity for these components. The cooling system known from German patent application DE 103 42 935 A1 is relatively complex.
German patent application DE 100 47 080 A1 discloses an internal combustion engine with a cylinder block and a cylinder head, each having coolant ducts that are part of a cooling circuit. Coolant is first conveyed by a coolant pump into a distributor strip which is integrated into the cylinder block and which is configured in the form of ducts that are open towards the separation plane towards the cylinder head. Starting from the distributor strip, the coolant flows into the coolant ducts of the cylinder block and into the coolant ducts of the cylinder head through openings in a cylinder head gasket installed between the cylinder block and the cylinder head. As a result, internal combustion engines that use identical cylinder blocks and cylinder heads can be adapted in terms of a distribution of the coolant between the cylinder block and the cylinder head in that cylinder head gaskets having differently dimensioned openings for the coolant are used.
German patent application DE 10 047 081 A1 discloses a combustion machine with a cooling system in which the flow of coolant through coolant ducts that are configured in a cylinder block on the one hand and in a cylinder head on the other hand can be regulated by means of a distributing unit using thermostat-controlled valves installed in the coolant ducts. In this context, it is provided that, during a warm-up phase of the combustion machine, the amount of coolant conveyed through the cylinder block is only what is necessary to expel vapor bubbles and to heat the thermostat-controlled valve situated there, and that the amount of coolant conveyed through the cylinder head is only what is needed to expel vapor bubbles, to heat the thermostat-controlled valve situated there and, if applicable, to provide the required heating capacity of a downstream heating heat exchanger.
Before the backdrop of this state of the art, the invention is based on the objective of making it possible to simply and inexpensively adapt the flow of coolant through the individual components of a combustion machine having a cooling system comprising several components.